Fuel Injector Selection
Make your injected car keep up with
hardcore modification using our parts
CAPA can supply an extremely large range of
fuel injectors for both performance and standard applications at extremely
competitive pricing. We have access to all of the major performance brands of
Fuel Injector ranging from Bosch to Rochester. We can supply individual
injectors that are capable of flowing up to 120hp! No matter what your project
is we have the injectors for it.
Selecting the Right Injector
In order to select the correct size injector for your application, you might
wish to use one of the following formulas.
In most cases a naturally aspirated engine will have a B.S.F.C of .50. This
means that the engine will use .50 lbs. of fuel per hour for each horsepower it
produces. Supercharged engines will want to be at .60 lbs. per hour or higher.
Using these numbers as a guideline, you can select the approximate injector size
in the following formula for a four cylinder, naturally aspirated engine at 200
bhp.
Most injectors will max out at 80% duty cycle and this is the accepted industry
standard.
B.S.F.C is brake specific fuel consumption
 How much fuel you are using per horsepower per hour
Horsepower x B.S.F.C
No. of injectors x .80
(duty cycle)

= 
200 x .50
3.2 
= 31.25 lbs. / hr. per
inj. x 10.50
= 328 cc / min 
The proper injector for this application would be 31 lbs. / hr. or 330 cc / min
To find the HP value of the of the
above mentioned injectors use this formula:
Inj. size (in lbs. / hr.), 31.25 x
(80% duty) / .50 B.S.F.C = 50 hp. per inj. x 4 inj. = 200hp.
 To
convert cc / min to lbs. / hr.  Divide by 10.5
 To convert lbs. / hr to
gal. / hr  Divide by 6
 To convert cc / min to
gal. / hr.  Multiply by .015873
To find the fuel flow
change from a fuel pressure change:
New PSI
Old PSI

x Old Flow = New
Flow 
To convert injector flow rates to horsepower potential  multiply static flow
rates by .80 and then use one of
the following formulas:
 To convert cc / min to horsepower  multiply by .190476 x number of injectors
 To convert lbs. / hr. to horseower  multiply by 2 x number of injectors
